1. Field of the Invention
The invention relates to a process for producing liquid pig iron or steel preproducts from fine-particulate iron oxide carriers and lumpy iron-containing material, such as partially and/or completely reduced sponge iron, in a meltdown gasifying zone of a melter gasifier, in which the iron-containing material, optionally upon previous complete reduction, is melted in a bed formed of solid carbon carriers, under the supply of carbon-containing material and oxygen-containing gas while simultaneously forming a reducing gas, wherein fine-particulate iron oxide carriers, such as iron-containing fine ore and ore dust and oxidic iron fine dust, are introduced into a reducing gas stream leaving the melter gasifier, the reducing gas is freed from the fine-particulate material formed therefrom, the separated fine-particulate material is introduced into the meltdown gasifying zone by means of a dust burner via a dust recirculation line and the reducing gas is used for reducing the iron-oxide-containing material, and a plant for carrying out the process.
2. Brief Description of the Related Art
A process of this type of known from EP-A-0 576 414. The known process allows to charge larger amounts of fine ore and/or ore dust, such as oxidic iron fine dust accumulating in a metallurgical plant, in addition to lump ore. The oxidic fine particles introduced into the reducing gas stream are conveyed into the meltdown gasifying zone of the melter gasifier via a dust recirculation line. The dust recirculation line is comprised of a dust sluice and a pneumatic conveying system as well as of a dust bumer, the dust sluice overcoming the pressure difference between the melter gasifier and the solids separator, for example a cyclone, which, in tum, frees the reducing gas from the fine particles.
However, a problem arises from the fact that the oxidic fine particles introduced into the meltdown gasifying zones have to be reduced yet. In order not to impair the meltdown and gasifying process in the meltdown gasifying zone, i.e. the generation of reducing gas, the amount of such oxidic fine particles that can be processed according to the known process is not very large.